Manufacture of hollow metal bars



Patented May 10, 1932V PAT-w+ "MccLnANE isnowN, onsnwIcKLEY, PENNSYLVANIA 'y MAN-Urncrunn or HOLLOW METAL BARS Application mea August 9, 1927. serial YNo. 211,710,

My inventionrefers tothemanufacture of metal articles such -as stay-bolts, rods, etc.,

capable of providing resistance,l tensile strength and ductility, Vwith a comparatively hard hollow center. 5 f l In the manufacture, for. instance, of staybolts for locomotive nre-boxes or similar uses,

it is desirable to provide a small axialperfd rationgfor leakage in case of fracture.'

Ordinarily, such perforationnis produced by drilling a small hole'centrally through thel article, andin the case offiron ormetals of various kinds,the character as to hardness iS. usuallyfunvarying throughout 'the section.

MetalV adapted to meetthe usuallstay-bolt andY similar specifications must be sufficiently` soft and ductile, with its other qualitie`s,;fory

the `necessaryultimate` strength, elongation,

and reduction of area. .The formation of the central-perforation byfdrilling through metal of such character, is diiiicult because of a lack of sufficient hardness or brittleness, tending to clogging as the drilling proceeds.L w

This results infgreat difficulty and rapid wear and breakage of thej'necessarily smallA drills used, .with an incidental high cost-of the product.` r

Inlmywpresent invention I utilize c in the manufacture of rods, bolts or other similar perforated articles are produced, anvingot, slab,bar,` or otherV raw material `Unitbriginally made of a pile-.0f metal, as muck bar or the like, asordinarily utilized in rolling mill practice. v Thereafter, the resulting ingotor billet or baris pierced, i'n the manner` commonly employed in the manufacture of seamless tubing, whereby to effect a completewelding and densication of the metal surrounding the pierced opening,

throughout its length. v Thereafter, a pieceof tubing coextensive with the length of thebar is inserted inthe pierced hole, with as close a fit as can be made, with a'filling of sand or other refractoryy materi'al, and'havi'ng itsends closed. There-- after, the `pierced bar as thus provided with the tube and its refractory 'core is ire-heated and then reduced by'rollingvor other suitable means, untilreduced to the' desired diameter,

and with; .an accompanying' proportional-ref etc., from which stay the piercing operation over a mandrel;flA

Fig. l is a cross sectional View of the piercedU Si bar, indicating the dense wall surrounding the central opening; l Fig. 5 is a partial longitudinal sectional view showing the pierced bar provided with the insertedV refractory filling tube;

Fig. 6 is across sectional view on the .line VI-VI of Fig. 5; l i" l Fig. 7 is a view in elevation, partly inV sec-L tion, 'of a stay-boltmadeas oneproductof the invention; .l-

n Fig. 8 is a cross sectional viewonthe line v VIII-VIII of Fig. 7.

Referring to the drawings, asia base or raw4 materialfon the ilinally rolledv rod or bar fromfwhich a stay-,bolto other article is made, a pile A, built up in the usual way of rolled bars vor othersimilar elements, scrap-,ete` y a The arrangement of the individual bars or y the like vis in anymanner suitable toplace-'f 85 ment in a heating furnaceand for the'usual' reduction to any desirable cross .sectin, as.A square, heXagon, round, etc.; i V 1 'In utilizing the invention forfthev making of hollow stay-bolts, the pileis preferably reduced tocylindricalform 2. invcross section, the originalV separating lines between Vthe Vine` dividual bars beinggenerally :indicatedjin dotted lines, asiat 3. When thusfrolled,the resulting bar of suitable diameter is generally lsimilar as to Vits.metallurgical characteristics throughout any 1 cross section, .dependent=\ of, course, ,uponz the analysis of` the Emuck bar or other material usedin the original pile. f .1.5 i

When` thusrolled', I then pierce the barcen-Y i loo' Y f opening from one endtoitheiother of Abai-12,

trally from end to end by the usual or any suitable cross rolling and piercing operation, preferably under the same heat,as indicated in Fig. 3, utilizing a mandrel 4 so as to penetrate the bar 2 from one end to the other, providing the opening 5. In such operation, the middle portionof thel bar, surrounding the opening, issub'ected to a severe densifyingpressure, effecting a complete Welding. together of the metal, in an annular zone surrounding the opening', and With added density, as indicated at 6.- In-this manner, v.a strong shell-like cavity is provided, with con-r siderably added resistance as tothe strength-A of the inner Wall portion, Which is of very considerable vadvantage inf. carrying? out the later'steps ofthe operation. l

rllhereafter,` a= tube 7, ofseamless tubing or other suitable pipe form, isfinsert'ed Within as in Fig.' 5. The'tube 7 is provided Witlra filling' of any suitable refractory material .8, as isand', tightlyfpa'cked. Within the tube. fromy one end to the other, the end-sbeing closed in anyffsuitable-Way, as by swedging. them toget-her, or by=plugs9i Asthus provided with `the central tube and its'l-refractory core, the bar is then relieated, suflicientfto permit of fur-therV reduction by rolling,;and the diameter of the bar-is brought down'. `to' suitable dimensions, adapting :it' to the making of stay-bolts, as shown: in Figs?. In such reduction, the tube 7 -is elongated and reduced ine diameter" and simultaneously- Welded to 'the surrounding fbar, during continuous'resistance ofthe refractoryl8,so that,

in the resulting finished length of bar, there is. provided a` continuous central opening l0 from. one end to the other,1and With correl spondingly reduced diameter in conformity structionalso admits-of easy free removal of the` refractory afterl the final rolling operations, eitherby airA or hydraulic pressure, or anyother suitable means.v 'Y

It'will be understood,ofi course, that'the relative:Y dimensions of:V the article, in the original lpile form andV with 1a VView `to the 'desiredeventual or4 final dimensions offtheresulting`articles,.fare Within the: easyy control of the manufacturer, andfthatanydesiredcross Sectional areaor bodyl portionlofi the pile or bar may be secured, utilizing suitable metal and in vieu7 of its extent of reduction in forging or rolling.

The advantages of the invention Will be readily 'understood and appreciated by all Athose familiar With the class of hollow staybolts andthe like, or of anyv articlesrequir-V ing' the provision of acentral .smoothf continuously open hole.

The original arrangement of the pile itself `may be ychanged or "varied-'Within thel judgment of themetallurgist or maker, and the invention is in no Way restricted to any arrangement of thelayers or sections or other speciiic metallurgicalV qualities orto any particular or speciiicshape-ofthe pileor. the iresultingf-product in crosszsection.v

l. The-method of rectangular bars consisting-in `rstl forming an: axial opening:V` through.: they 4rolled bari With surrounding condens ation, y .then inserhf iner Within` the bar a-metal tube .'.containng'a re ractory material, and thenf redueingfthe bar and l'welding it. to the tube :ibyf pressure.; The methodofmaking a hollow center:

bar or/the like from'la-vpreviouslfy.rolledapile of bars arranged -in horizontal series consist-1 ing `in rstforming an axial opening;.;through thel rolled bar with' surroundingcondensatiom. then inserting Within the bar; a: .metal ftube.

containing refractory-1' materiah. and:l then heating and reducingthe lbar andrtubefby'.

external reducing andk Weldingpressure'. y f

3. The method ofmaking a;hollolw center: bar or theflike consisting/in first assembling a pile of rectangularpeces, .rolling-thesaine:

to cylindrical 5 form, then forming an'. axial opening'throu'gh the roller barfwith sur;

rounding` condensation,V then-inserting Withfv in the bar a metal tube containing refractory material, rand then heating and reducingthe bar and tubey with compensating:elongation:

by external reducing and Weldingpressure.

4'. The method vl,ofI makingA af hollowcenterf bar or the like consisting in .firstz reducingza rectangularpile of piecesto cylindrical form,- then `piercing the bar llongitudinally WithY ac.- compan-ying condensation;l of= the. surrounde ing metal, then inserting arefractory. filleul` metaly tube, and thenfheating, rolling; and4 Welding the bar and tubeztogether.

ofmaking la; hollowl a center f bar or the like from apreviouslyirolled pile ma y "los

no l

jns

5. The method ofimakingfauhollow center bar or the like consisting in first reduoinga rectangular pile of piecesto cylindricallfrm, then piercing the bar longitudinally Withac'e companying condensation ofthe surrounding metal, then inserting a'refractory filledmetal tube, and thenheating, the bar and tube together.- refractoryfrom Vthe tube.

v 6. The methodof'makingahollowz center bar or the like` consisting.l in assembling a pile of rectangular pieces-1 of metal andere and removing the rolling and'v Welding ducing the same to cylindrical form under heat by rolling7 then piercing the center of the resulting bar, then inserting a refractory filled metal tube, and thenV subjecting the combined bar, tube and refractory core to heat and further rolling and Welding.

7 The method of making a hollow center bar or the like consisting in assembling va pile of rectangular pieces of metal and reducing the same to cylindrical form under heat by rollin then piercing the center of the resultin ar, then inserting a refractory filled tu e, and then subjecting the combined bar, tube and refractory' core to heat and further rolling and welding 'with final removal of the refractory.

8. A hollow metal bar consisting of a main outer integral densified body portion formed from a variously distorted elemental rolled cylindrical blank having a central metal tube incorporated by welding with'the surround.

ing densiied inner portion of the outer body portion. A/

9. A hollow metal bar consisting of a main outer integral densie'd body portion formed from a variously, distorted elemental rolled cylindrical blank having a Central metal tube incorporated by welding withthe surroundf ing densified inner portion of the outer body portion and welded thereto.

In testlmony whereof I hereunto afx my i signature.

MCCLEANE BROWN. l'

CERTIFICATE OF CORRECTION.

Patent No. 1,857,620. May 10, 1932. p

McCLEANE BROWN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction` as follows: Page 2, line 105, claim 3, ior the word "roller" read rolled; and that the saidLetters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 12th day of July, A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

